The present invention relates to a surgical instrument and in particular to an instrument for fine micro-surgery and endoscopic surgery.
A number of surgical instruments have been developed for use in micro-surgical and endosurgical procedures wherein it is impossible to make a large opening in the body although the instrument must be manipulated in various angles deep within the body. In general, such instruments comprise a fixed blade mounted at the distal end of a shaft and a moving blade mounted on the distal end of a linking rod that is slidable axially with respect to the shaft. The distal ends of the shafts are attached to a scissor grip handle for holding in a single hand. Manipulation of the handle causes the linking rod to in turn cause the movable blade attached to it to pivot in a shearing relationship with the fixed blade. Such devices are shown, for example, in U.S. Pat. Nos. 984,756; 1,754,806; and 3,585,985.
A disadvantage of the above examples lay in the fact that in order to adjust the direction of the working end relative to the axis of the combined shaft and rod from angle to angle, it was necessary for the surgeon to bodily rotate or move the entire instrument which necessitated twisting not only the instrument, but the hand and arm of the surgeon. Alternatively, the surgeon would remove his hand from the scissor grip and independently translate the position of the instrument from one direction to another and thereafter reinsert his hand on the scissor grip.
In U.S. Pat. No. 4,248,716 an instrument is disclosed which has as its purpose the avoidance of a structure wherein axially reciprocal rods and shafts are provided. In this patent, a rotatable rod is mounted within an elongated hollow shaft at the end of which are shearing members, which come into shearing engagement on the rotation of the internal rotatable shaft. In addition, the instrument has a barrel-like handle, a depressible finger mechanism and means for converting the linear motion of the finger mechanism into the rotary motion required to manipulate the rod. With this instrument, it was believed that the problem with regard to the orientation of the cutting end would be eased. However, this was, in fact, not obtained since the blades still were fixed in position relative to the axis of the instrument and the surgeon still had the disadvantage of having to bodily rotate the instrument into a particular angular position as well as the added disadvantage of having to depress a finger mechanism against a barrel-type handle.
A similar device is disclosed in U.S. Pat. No. 4,433,687 in which a micro-surgical instrument is shown wherein two sections of a barrel handle are compressed to rotate an inner mechanism whose rotary motion is converted into a linear motion to draw a pair of blades together. This device has not had any commercial success, suffering from the same disadvantage as the other exemplary disclosures.
It is an object of the present invention to overcome the disadvantages of the prior art micro-surgical devices and to provide an instrument which is efficient, easy to use in a single hand, and wherein the angle of attack of the working tools are readily adjusted by single finger manipulation, independently of the motion causing shearing action.
A further object is to provide a surgical instrument having a simple reciprocating rod and shaft mechanism of extremely small diameter that can be inserted into a relatively small field of operation without undue trauma or disruption of tissue, and which is easily oriented in situ.
It is a further object of the present invention to provide a surgical instrument which is operable in a single scissor hand grip in a manner familiar to and with which the surgeon has a great deal of experience.
These objects and advantages together with others will be apparent from the following disclosure.